Plasmon-enhanced water and carbon dioxide splitting

Effects based on localised surface plasmon resonance are utilised
for enhancing surface chemical reactions. Of particular interest are
water and carbon dioxide splitting under direct solar irradiation
for production of hydrogen and carbon monoxide.
Typically, a semiconductor such as titanium dioxide is
used to transfer electrons
in water or carbon dioxide splitting.
Limiting factors for these designs are insufficient absorption
near the surface of the semiconductor and a relatively low reaction rate.

Fig. 1.
A silver nanoparticle on silicon,
showing the high electromagnetic field around the nanoparticle.

In this project, we aim to use metal nanoparticles on the surface
of a semiconductor to enhance the surface chemical reactions.
When light hits a metal nanoparticle, it can cause all the electrons
within the particle to oscillate back and forth together,
known as a plasmon resonance.
This creates a giant electromagnetic field around the particle,
as illustrated in Fig. 1,
leading to strong absorption of light and generation
of energetic electrons in the nanoparticle.
In addition, the metal has a high density of free electrons, which can speed
up the rate of chemical reactions near the nanoparticle.
This approach is a promising way of achieving a cheap, efficient
way of producing solar fuels.